I dropped documents at Visa application center ( at parinee crescenzo) in Mumbai on 18th June.
I carried photos from CVS in USA which was approved by their software for all the requirements. Still the staff at document collection center refused to take those pics and had me taken the pics at right next to their office. they charged Rs.400 for four photos.
Tip: Take some money with you in case are asked to take pictures. Do not carry phones. The same place that took my pics, charges Rs. 400 to store your phone if you carried the phone with you.
Anyway coming back to documents. They will only take your I-797 copy, passport and pictures.
Got the phone from the blue dart to pick up my passport on 22nd june. When i went to pick up passport, I found the green slip to appear for interview. I was prepared for it anyway so did not find it strange. you can go for interview any day between 10:30 to 11.
Important tip: please check the ustraveldocs website for their holiday schedule before going for interview. Be very careful to check following
https://in.usembassy.gov/wp-content/uploads/sites/71/visaholidays.pdf
These are additional holidays in addition to their official holidays. ( They should include all this holidays on one page instead of giving the separate link for pdf file). I had interview on 27th June. Visa officer approved the visa. For 3 business days, online status showed administrative process. On 3rd, the online status showed visa issued. on 4th I received passport from Blue dart.